1. Field of the Invention
This invention is directed to a high-speed and high efficiency image processing system of a plane scanning type. This invention relates more particularly to an image processing system arranged as follows. A color original is read by rough prescanning, the read data is stored, conditional parameters are set, and the color original is read by fine main scanning and processed. An image of the color original is efficiently recorded on a photosensitive material, thus preparing a printing plate. Besides, there can be selected either a speed preference mode to reduce a scanning time or a photosensitive material consumption preference mode to decrease consumption of the photosentitive material. Independently of these modes, there can be indicated a quality preference mode to enhance an output by increasing a read resolution in an input unit.
2. Description of the Prior Art
The following is a description of a conventional method of preparing color separations. A plurality of color originals are laid out per color separation. For this purpose, a halftone color separation film is prepared with a predetermined magnification by use of a color scanner. A mask plate prepared by a separate process and the halftone color separation film are allocated on a layout sheet, and each original is stuck. Contact exposure is then effected, thereby preparing a laid-out color separation. This method, however, presents the following defects. This method is large in the number of processes and also complicated. A highly skillful technique is required, wherein the color separation is disposed in the neighborhood of a predetermined position and stuck onto the layout sheet. A good deal of time, labor and materials are also needed. The plurality of color originals are color-printed at specified magnifications. The prepared duplicated original is cut out into a predetermined block copy pattern. The pattern is stuck in a predetermined position of a block copy layout sheet. A laid-out color image is then copied. This method is, however, based on a photographic technique. It is therefore impossible to freely change a color correction process, a sharpness emphasis and a gradation conversion process. This is a problem in terms of an image quality. Besides, a system (e.g., Japanese Patent Publication No. 31762/1977) for simultaneously layout-outputting rectangular images by a plurality of input devices has the following defects. It is hard to correspond to arbitrary graphics. Preparation of the mask plate requires labor. Inputting of the color originals needs a plurality of input scanning units.
In recent years, there has been proposed a layout retouch system known as a so-called total system in the process of preparing prints. In this system, the graphic is inputted by a digitizer. The graphic and an image (pictorial pattern) are displayed on a color CRT. The color original is, however, scanned at a specified magnification by a color scanner. After effecting an A/D conversion, the color original information is stored in a storage unit. The color original information stored therein is displayed on the color CRT in accordance with the input graphic information. Editing is carried out within a main storage unit of a computer by an interactive input. The information is stored again in a magnetic disk or the like in a format corresponding to the output picture. Subsequently, the color image information corresponding to the output picture after being edited undergoes a D/A conversion. The thus converted information is thereafter inputted to an output control circuit of the color scanner. A desired layout image is thereby obtained. There arise, however, the following defects inherent in the layout retouch system described above. A large capacity storage medium is needed for storing the information on the color originals. A high-speed computer is also required for the editing process. The system construction is very costly. The editing process also takes a large amount of time.
To obviate those defects, an image input/output system (Japanese Patent Laid-open No. 11062/1984) depicted in FIG. 1 was proposed. A color original 2 is stuck onto a rotary input drum 1. The color original 2 is spottily image-outputted onto a recording material or a color paper 11 stuck onto a rotary output drum 10. This image-outputting is based on the information which has been graphic-inputted by a digitizer 14 serving as a graphic input device. The color original 2 is spottily scanned by a read head 21 and is thereby color-separated. Color separation signals CS obtained by reading the image information are inputted to a logarithmic converting circuit 3. The logarithmic converting circuit 3 converts the color separation signals CS into density signals DN. Thereafter, the density signals DN are converted into digital signals DS in an A/D converter 4. The digital density signals DS are inputted to a signal processing section 5 and a micro-processor 12 as well. The signal processing section 5 performs color processes such as a color correction, sharpness emphasis and a gradation conversion. Color-processed image information DSA are converted into analog signals by a D/A converter 6. The analog signals are inputted to a modulator 8 incorporated into a laser beam printer. Laser beams emerging from a laser oscillator 7 are modulated. The color paper 11 stuck onto the output drum 10 is spottily exposed to the modulated laer beams through an output head (not illustrated).
On the other hand, a console 16 equipped with a keyboard is prepared as a data/instruction input device. The data inputted from the console 16 is further inputted to a computer 13. The information processed by the computer 13 is displayed on an interactive type graphic display 15. The computer 13 is connected to a microprocessor 12 as a low-order system. The density signals DS coming from the A/D converter 4 are inputted to the microprocessor 12 connected to the signal processing section 5. An arithmetic operation is effected therein. Note that the computer 13 and the microprocessor 12 are combined to constitute a computer system. An instruction to the operator is displayed on the graphic display 15 in accordance with a program incorporated therein. Positions of the input and output drums 1 and 10 are detected by an unillustrated detector. The positional information thereof is inputted to a motion control section 9. The motion control section 9 is connected to the microprocessor 12 so that the control unit 9 relatively drive-controls a positional relation between the input drum 1 and the output drum 10. The digitizer 14 has an X-Y axis and original point coordinates intrinsic to the device. The digitizer 14 is capable of moving the original point to an arbitrary point by signal processing and easily rotating the coordinates. A corresponding relation between the digitizer 14 and the position of image on the input drum 1 is established by providing guides such as pins in a plurality of common positions. The digitizer 14 is connected to the computer 13, whereby an image configuration and desired positional coordinates can be inputted.
The image input/output system described above, however, has the following defects. When reading the original, as illustrated in FIG. 2, the color original 2 is stuck directly to the cylindrical input drum 1 formed of an acrylic resin, glass or the like to have a smooth transparent surface. The color original 2 is irradiated with the light emerging from a light source 20 provided inwardly of the input drum 1. Transmitted light from the color original 2 is received by a read head 21, whereby an image of the original 2 is inputted, In this case, if a gap equivalent to a wave length of light of the light source 20 is formed between the color original 2 and the input drum 1. Newton's ring (interference fringes) is caused due to interference action of the light between the underside of the color original 2 and the surface of the input drum 1. Newton's ring appears as a fringe-like ununiformity in density on the color original 2, resulting in a remarkable in quality of the original. To prevent such interference fringes, powders of hyperfine particles have hitherto been spread between the color original 2 and the input drum 1, or alternatively fillers have been applied therebetween. The powders have such defects that the particles become visible when increasing the image magnification, and the powders are hard to deal with. The fillers also have defects, wherein it is troublesome to apply and wipe off the fillers.
The image input/output system such as a total color scanner is arranged as follows. Ths system inputs the image information of an original film or the like. After performing enlargement/reduction thereof, the image information is outputted in an arbitrary layout. The original is read in the same way with the case of FIG. 2. In the image input/output system, however, it is required to know the coordinates of the color original 2 on the input drum 1 when reading the original for the layout. For this purpose, in the prior art, as illustrated in FIG. 3, the color original 2 is stuck onto a transparent rectangular sheet-like original sticking base 22 having a thickness of 100 .mu.m by use of sticking tapes 23. Corresponding pins of the digitizer are fitted in positioning holes 24. The coordinates of a necessary portion of the color original 2 are inputted to the image input/output system. Thereafter, as depicted in FIG. 4, corresponding pins 25 of the input drum 1 are fitted in positioning holes 24 formed in the base 22, thus attaching the base. The color original 2 is, as in the same way with the case of FIG. 2, irradiated with the light emerging from the light source 20 provided inwardly of the input drum 1. The read head 21 receives the transmitted light LT travelling from the color original 2. An image of the color original is thereby inputted. The layout process is effected with a correspondence to the coordinates inputted by the digitizer.
The conventional color scanner requires a skillful operator to determine the separating conditions. Besides, the time for determining the separating conditions is longer than the time for which the scanner actually rotates. Furthermore, the conventional color scanner is intricate in operation, and a psychological load on the operator of the scanner is large.
A color sepration scanner has been developed to obviate the defects incidental to the above-described drum type color scanner. This color separation scanner performs the process by reading the color original by a plane scanning method with a TV camera. This type of scanner also presents problems in terms of a speed-up of the reading process and an efficiency as well. An additional problem is that setting of the processing conditional parameters is troublesome.
In the image processing systems including the conventional color scanner and image input/output system, there is given no consideration to show what kind of status the original may assume when reading the image. This is the real situation. For this reason, a big loss in consumption of the photosensitive material is caused depending on the original reading directions. In addition, a large utility of the scan reading time of the input original is also produced. The user of the image processing system therefore demands for enhancing the output quality by increasing the read resolving power in the input unit.